A drop in the Southern Ocean: A23 begins

Tuesday 8th April

We are further east now, and despite the temperature being up at a relatively toasty -12.6 °C the surrounding water is still fairly solid. The ship jumps and judders as we break through the sea ice, making huge scraping and thumping noises. Heather is still a little convinced that we are going to sink with every big bang and bump! Its very beautiful though. Driving the ship through ice is hard work for the bridge officers. Our Captain Jerry and first mate Tim are working long hours supporting Phillipa and Greg, the 2nd and 3rd Officers who are having their first experience driving in ice. Tim says its great fun though and a little like off-roading back on land!

Siobhan braves the cold (photo by Pete)

We have started a line of sampling that will take us north towards South Georgia (A23). At the south end of the line we are looking for some deep bottom waters that form in the Weddell Sea, and are too cold and dense to escape out into the rest of the Southern Ocean. By measuring the concentration of CFCs in these waters we hope to find out how long the water masses have been there. These bottom waters could be quite recently formed, sinking around Antarctica as sea ice forms. Conversely they could be very old, and just too cold and dense to go anywhere. The ages of these bottom waters will give us an idea of the physical processes at work in the Weddell Sea.

More ice...and the trusty lifeboats!

Further north and closer to South Georgia we will be on the look out for the DIMES tracer. The Polar Front meanders north of South Georgia, leaving the Scotia Sea through a gap in the middle of the North Scotia Ridge. We think most of the tracer went with the Polar Front, but we hope to find out just how much made it over here.

Smoking wake (photo by Pete)

Sampling is hard in such freezing temperatures, The CTD freezes as we take it out of the (relatively) warm sea and the biting air hits it. The little taps on the CTD where we collect our samples freeze solid, and have to be warmed by our hands until the water flows. Brrr! Luckily we have lots of excellent playlists complied just for sampling so we can keep ourselves warm by singing and dancing away!